How to apply a hair particle effect to a specific material
You could use weigth painting. Select your object and go to the Data tab (triangle) in the Properties window. There is a section called Vertex Groups. Click the + icon to create a new vertex group and give it a name. Now you can switch from Object Mode to Weight Paint mode and paint the verts where you want your particles to appear. Blue = no particles, red = 100% of particles.
Afterwards go to your Particles tab, scroll down and open the Vertex Groups section. Click next to Density and select the vertex group you just painted.

(can't provide pics right now, sorry)